In the related art, in various treatments such as etching or sputtering of a manufacturing line of a semiconductor device such as IC, LSI, and VLSI, components configured of ceramics such as alumina have been widely used. For example, as a ceramic part in the semiconductor manufacturing device, an electrostatic chuck is included.
The electrostatic chuck is required to have high adhesiveness, excellent thermal conductivity, and durability as a support mechanism of a semiconductor substrate such as a silicon wafer. The electrostatic chuck includes an approximately disk-like insulating body on which the semiconductor substrate is mounted, and an electrostatic attracting internal electrode which is embedded in the insulating body, and a direct-current voltage is applied between the insulating body and the semiconductor substrate mounted on the insulating body, and thus a Coulomb force or an electrostatic attracting force due to a minor leaked current is generated, and the semiconductor substrate is fixed to the insulating body by the electrostatic attracting force.
As the insulating body used in the electrostatic chuck, ceramics such as aluminum oxide and aluminum nitride have been generally used.
In particular, the ceramics are excellent for thermal conductivity and plasma resistance, but are rarely mixed with the substrate due to hardness thereof, and thus when the semiconductor substrate is transported, a flaw, a crack, or the like may occur, or degradation of insulation properties which is caused by using the semiconductor substrate over a long period of time and insulation breakdown caused by damage due to plasma or corrosive gas may occur, and an element on the semiconductor substrate may be broken during the various treatment such as etching or sputtering.
Therefore, as a technology of detecting the insulation breakdown of the insulating body of the electrostatic chuck, a technology is proposed in which a current detector is disposed in a circuit of an electric source connected to the electrostatic chuck, the insulation breakdown of the insulating body is detected, and continuous use of the electrostatic chuck in which the insulation breakdown occurs is prevented (refer to Patent Literature Nos. 1, 2, and the like).
In addition, a technology is proposed in which a potential difference between the electrostatic attracting internal electrode of the electrostatic chuck and a ground electrode is measured, and thus the insulation breakdown of the insulating body is detected (refer to Patent Literature No. 3 and the like).
In addition, an electrostatic chuck using a porous dielectric instead of the insulating body is proposed (refer to Patent Literature No. 4 and the like). In the electrostatic chuck, a diagnostic method for preventing insulation breakdown due to adsorption of moisture is adopted.